1. Field of the Invention
The present invention generally relates to integrated circuits, and more specifically to a memory point formed over several metal and via levels that can be reprogrammed by modification of any metal or via level.
2. Discussion of the Related Art
Integrated circuits are increasingly complex and it is often necessary to modify a circuit several times after testing and evaluation by the user. Currently, there can be from three to ten successive versions of the same circuit. From one version to another, the circuit modifications are conventionally performed by redefining the metal connections on a single metal level or a single via level.
It is desirable to be able to indicate to which version a given circuit belongs. This can be done by marking the chip or the package. These two solutions raise problems of manufacturing and use. Solutions enabling, by an electric testing, determination of the version, require providing a storage means in the circuit that can be updated upon successive modifications of the circuit. However, known conventional means are not adapted to be simply modified upon redefinition of a single metal level or of a single via level.